Table of Content

20 August 2018 Volume 38 Issue 4

  

Roller Control at an Away-from-reactor NPP Radioactive Waste Treatment Center

Xue Yanjun, Ma Xiaoqiang, Zhang Sushan

RADIATION PROTECTION BULLETIN. 2018, 38(4):  1-7. 

Abstract ( 78 )   PDF (1465KB) ( 107 )  

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As the core equipment for NPP radioactive solid waste flow, the roller conveyor is responsible for the transfer of drums containing various wastes. Its reliability, stability and safety are related to the normal operation of the solid waste treatment production line. This paper introduces the function, composition, process and improvement scheme of the roller control system at an NPP away-from-reactor radioactive waste treatment center, so as to achieve fully automatic drum transfer, avoid excessive radiation exposure to operators, and ensure safe and efficient operation of the process.

A New Process for Treatment of Radioactive Waste Plastics by High Temperature Melting Technology

Zhan Jing, Rong Yun, Wang Chengdong, Shen Lifeng, Lan Jiang

RADIATION PROTECTION BULLETIN. 2018, 38(4):  8-13. 

Abstract ( 58 )   PDF (1919KB) ( 113 )  

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There are many kinds of radioactive waste plastics produced by NPPs, which are now mostly treated by compression or incineration. While compression may cause drum burst and pellet rebound, resulting in waste volume increase; incineration produces toxic and harmful gases that pollute the environment. A new process is proposed, which adopt a flow of sorting, crushing, melting, pre-pressing and natural solidification, and supporting equipments are designed. After analysis and debugging of parameters, the volume reduction ratio of the process to treat radioactive waste plastics can reach 15.4.

Pellet Loading Program Optimization for a NPP Radioactive Waste Supercompactor

Yu Bo, Wang Zaiheng, Lin Chuanyu, Han Xiaodong, Wang Zhanpeng

RADIATION PROTECTION BULLETIN. 2018, 38(4):  14-19. 

Abstract ( 63 )   PDF (805KB) ( 99 )  

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From the point of view of radioactive waste minimization, the loading process of pellets resulted from waste supercompaction in a NPP is simplified into a bin-packing issue. In combination with the optimal algorithm of descending order, an optimized scheme of loading is proposed, and simulation operations are carried out. The results show that the scheme can significantly improve the loading rate of repackaging drums. The feasibility of the scheme is proved by comparison and analysis of the storage, transportation and loading efficiency of waste pellets.

Radiation Safety Analysis of X-ray Rapid Safety Inspection System

Deng Yanli, Ming Shenjin, Zhu Guoping, Wang Bing, Li Junli, Miao Qitian, Zhan Hui

RADIATION PROTECTION BULLETIN. 2018, 38(4):  20-26. 

Abstract ( 68 )   PDF (896KB) ( 28 )  

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The X-ray rapid safety inspection system is a system for rapid and safe inspection of large quantities of incoming and outgoing container cargo at ports, logistics centers, highway bayonets and other places. Such a system, developed by Nuctech, uses a means of driving truck directly through the inspection channel to realize rapid inspection. The workflow of this system is introduced. The risks for drivers being accidentally scanned under normal working conditions, and for personnel breaking into or hiding in containers, are examined. And the safety risks under design basis accidents are analyzed as well. The results show that the system is safe and acceptable. An average member of the critical group of drivers receives a dose less than the relevant standards, while the dose to any personnel breaking into the inspection channel is as low as 4 μSv, which has no health impact.

Numerical Simulation Domain Analysis of Liquid Effluent Discharge from NPPs

Mao Yuanyi, Chen Yu

RADIATION PROTECTION BULLETIN. 2018, 38(4):  27-32. 

Abstract ( 75 )   PDF (16966KB) ( 50 )  

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In view of the dilution and diffusion of liquid effluents from NPPs in the receiving water, the two-dimensional numerical simulation method is often used for analysis. And the calculated flow field is often verified by hydrological test data. However, for radionuclides with longer half-life, the reduced fraction resulted from decay is smaller, and the size of calculation range has a greater impact on the calculation results. Combined with engineering examples, two computational domains with different sizes are selected, numerical simulations are carried out respectively, and the calculated flow regime, concentration, flux and total conservation are compared and analyzed. It turned out that within the scope of computing power, a larger computational domain should be selected; under the condition of satisfying the calculation accuracy and efficiency, the range between the discharge outlet and the calculation boundary should be more than 80 km. The results can be used as a reference for calculating the computational range of NPP liquid effluents.

Status of Research on Interception of Wet Deposited Radionuclide by Crops

Han Baohua, Guo Shuyang, Zhang Sheng, Zhang Chao, Cao Shaofei, Wang Huijuan

RADIATION PROTECTION BULLETIN. 2018, 38(4):  33-36. 

Abstract ( 67 )   PDF (537KB) ( 56 )  

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Radionuclides released during the operation of nuclear facilities deposited on the surface of soil or crops and into the food chain, is the main source for calculating the internal dose to the public. The process of wet deposition involves the behavior of interception and translocation of radionuclides by crops. The research status of interception in rainfall pathways at home and abroad was overviewed, including crop species, experimental methods, influencing factors and transfer parameters. In view of the current situation in China, the research focus and direction in this field are put forward.

Some Suggestions for Measuring ²²⁶Ra in Water by Emanation Scintillation Method

Feng Yingsi, Jiang Lan, Zhang Yanjin, Deng Fei

RADIATION PROTECTION BULLETIN. 2018, 38(4):  37-40. 

Abstract ( 85 )   PDF (484KB) ( 106 )  

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The influence of air intake system, scintillation chamber calibration, measuring time and other factors on ²²⁶Ra measurement in water by the emanation scintillation method is analyzed. Suggestions for optimization are further proposed as follows: simplifying the intake system and flushing the scintillation chamber and gas path with pure nitrogen; prolonging the sealing time of the standard source, so that the cumulative factor is greater than 0.9, which can improve the stability of the K value of the scintillation chamber; increasing the sample size and measuring time to improve the measurement accuracy, for samples with low radium content.